Abstract: Method of and apparatus for sorting tobacco into two groups: a group of satisfactory leaves and a group of unsatisfactory leaves. Tobacco leaves, spaced so that they pass one by one along a conveyor, travel through a zone illuminated by pulsed polychromatic light and an optical sensor receiving light reflected from the tobacco leaves. In a manner which is synchronous with the pulsations of light there is measured the quantity of the light reflected by each of the leaves in the green, orange, red, and infrared areas of the spectrum. Sums are formed from the values corresponding to the reflected light in such areas of the spectrum and relations are obtained between sums corresponding to the green and orange as well as to the red and infrared ranges, of time in which the value of the reflected light in the infrared area is greater than a value preliminarily preset by the operator.

Abstract: Device for determining the reflective properties of objects in discrete spectral zones. The device has a housing in which there is disposed a diaphragm perpendicularly to the optical axis of the device and photosensors sensitive to light in a narrow spectral range that are connected with electronic amplifiers. The opening of the diaphragm coincides with the basic aperture of vision. Between the diaphragm and the object there are disposed supplementary diaphragms with openings coinciding with the basic aperture of vision. Each supplementary diaphragm lies in a plane determined by the intersection point of the parasitic aperture of vision of the diaphragm preceding it on the side of the photosensors and the housing. The device may be use to advantage in color discriminating systems, for example, the sorting of tobacco leaves according to their color.